1. Field of the Invention
This invention relates to the field of exercise equipment, and particularly to an exercise machine in which at least a substantial portion of the exercise resistance is provided by the body weight of the operator.
2. Background Art
A wide variety of exercise machines have been developed for exercising various muscle groups of the body. Most such machines employ weights to provide resistance to the operator's exercise movements. Most commonly, a stack of individual weight plates is provided in an arrangement such that a selected number of the weight plates may be coupled to the exercise station by a cable, lever mechanism or other device. Exercise machines of this type typically have a weight stack with a total weight of 200 to 300 pounds. Such weights represent a significant fraction of the cost of an exercise machine, especially when transportation costs are considered. Moreover, conventional weight plates are noisy when the exercise machine is in use.
The use of a person's own body weight as a source of exercise resistance is, of course, well known. For example, many calisthenic exercises, such as push-ups, sit-ups and the like, employ body weight as a source of exercise resistance. Several types of exercise apparatus that use body weight resistance have been commercially introduced. For example, the HealthRider.RTM. is a device for simultaneously exercising muscle groups of the upper and lower body in which the operator is alternately raised and lowered on a seat by operation of the apparatus. The Total Gym.RTM., marketed by EFI/Total Gym, employs an inclined sled to support the operator. Various exercises available with this machine cause the sled to be pulled up the incline as the operator exercises. The Body Force.TM., marketed by Maximus, provides a selectable amount of assistance to an operator while performing body weight exercises such as dips and chin-ups. The Gravity Edge.TM. has a pivoted platform on which the operator is supported in either a sitting or standing position. The platform is coupled by linkage to an exercise arm such that operation of the exercise arm causes the platform to be lifted.
Other variations of body weight exercise machines are shown in U.S. Pat. Nos. 4,632,390 and 4,949,958, both issued to Richey. These patents disclose devices in which an operator is supported on a generally horizontal bench which is lifted by various exercises. A roller and lever arm arrangement provides adjustment for the amount of body weight that is communicated as exercise resistance.
The various body weight resistance machines mentioned above provide a relatively limited selection of exercises compared to more conventional multi-station exercise machines that employ weight stacks. The latter class of machines has found wide acceptance among exercisers in both the home and health club markets. There is a perceived need for an exercise machine that combines the exercise flexibility of a conventional multi-station exercise machine with the advantages of a machine that derives exercise resistance from the operator's own body weight.